WTD; All mountain wheelset

Evening all, I'm after an all mountain wheelset for my zesty. Needs to be 15mm fr and 142x12 rear. The cross rides it has come with are too flexy, so after something a bit stronger. I have around £150 to spend.

I have a set of Sun Ringle XMB DTC wheels
Black rims, anodized red hubs
I have had up to 26x2.4 schwalbes on them and they fit nicely.
Both wheels run straight and true and have had very little use, only reason i took them off is because i was offered a set of crossmaxes at a very low price.
15mm front 142x12 rear as requested